post_install() {
    usr/bin/systemd-tmpfiles --create graylog-server.conf

	# this specific upgrade was don by replacing graylog2 with graylog; therefore we are uninstalled&reinstalled
	cat <<EOF
Major upgrade; graylog2 has been renamed to graylog and the following files where renamed:
 * /etc/graylog2.conf to /etc/graylog/server/server.conf
 * /etc/graylog2-server-node-id to /etc/graylog/server/node-id

You can copy your 0.9x config but you should add
 * message_journal_enabled = true
 * message_journal_dir = /usr/lib/graylog/data/journal

also; don't forget to update the node_id_file
EOF
}